FOXO信号在纳米级碳黑遗传毒性中的作用及机制研究

As an industrical product, carbon black floats in the air easily and induces damages to health. In the evaluation report of IARC, carbon black can induce genetic damages and there is inadequate evidence in humans for the carcinogenicity of carbon black because of the lacking of epidemiological evidences solely exposed to carbon black. The mechanism of damages induced by carbon black is not known very clearly. In the present project, the unique carbon black packers are chosen as the research objects. At meantime, the mouse and cell line will be used to establish the nanoscaled carbon black particles exposure models. In our previouse study, we found the mechanism of damages induced by nanoscaled carbon black particles was regulated by FOXO. Based on these results, the cell colony and flow cytometry sorting were used to evaluate the ability of cell transformation and gene mutation. The gene recombination、kinase activity analysis、ChIP、qRT-PCR, Western blot was used to test the genotoxicity and the mechanism through FOXO signal induced by carbon black. The present project will look for the sensitive biomarkers and early health effect indexes induced by nanoscaled black carbon particles before the advent of respiratory diseases and genetic damages end point by combination of field and laboratory research. The regulation of FOXO will be studied to explore the mechanism of genotoxicity induced by nanoscaled carbon black particles.

碳黑是一种应用广泛的工业产品，因其质量轻、粒径小，极易漂浮于空气中通过呼吸道进入人体而导致健康损害。IARC的评估报告认为碳黑可致遗传损害，但缺乏单纯碳黑暴露人群流行病学数据，导致碳黑致遗传损伤和肺癌的人群证据不足，并且损伤机制不清。本项目建立了单纯的职业碳黑暴露队列，同时建立吸入染毒的小鼠模型和细胞染毒模型，以课题组前期发现的纳米级碳黑诱导的损伤与FOXO信号有关的研究结果为切入点，采用基因克隆、ChIP、流式细胞分选等技术，将现场与实验室研究有机结合，探讨纳米级碳黑致DNA损伤、基因突变等遗传毒性，寻找纳米级碳黑在致人群呼吸系统疾病和遗传损伤终点出现之前的早期健康效应指标，阐明FOXO介导的信号途径在纳米级碳黑遗传毒性中的作用机制。

碳黑是一种应用广泛的工业产品，因其质量轻、粒径小，极易漂浮于空气中通过呼吸道进入人体而导致健康损害。IARC的评估报告认为碳黑可致遗传损害，但缺乏单纯碳黑暴露人群流行病学数据，导致碳黑致遗传损伤和肺癌的人群证据不足，并且损伤机制不清。本项目对碳黑的物理化学特性进行了表征，通过扫描电子显微镜和透射电子显微镜观察碳黑颗粒大体呈葡萄球状，分散性较好，颗粒直径大约为30~50 nm之间。建立了单纯的职业碳黑暴露队列，纳米级碳黑吸入后引起工人肺功能下降，血清中炎症细胞因子表达增加，提示炎症反应在纳米级碳黑引起的肺功能下降中起重要的作用。建立动式吸入染毒的大鼠模型和细胞染毒模型，结果表明，吸入纳米级碳黑可在肺组织沉积，且短期内不能排除体外，进入肺组织的碳黑可致肺组织炎性细胞浸润，肺组织纤维化，形成肉芽肿；电子显微镜下可见肺泡腔和巨噬细胞中有碳黑颗粒，肺泡型上皮细胞的微绒毛以及板层小体消失，核周隙增宽，细胞器减少，可见气血屏障纤维化。肺组织或支气管上皮细胞DNA损伤、微核形成、DNA损伤修复能力下降，产生遗传毒性。动物和细胞实验进一步研究纳米级碳黑导致肺组织损伤的机制，结果显示，（1）纳米级碳黑可引起大鼠血清中代谢组改变，主要包括激素代谢、氨基酸代谢、核苷酸代谢和脂质代谢紊乱。（2）大鼠免疫系统损伤，胸腺和脾脏组织病理学改变，淋巴细胞增殖能力下降，胸腺细胞凋亡，免疫功能下降；（3）PLK1介导的FOXO信号通路激活是碳黑诱导的遗传损伤的机制之一；（4）MiR-96靶向FOXO3a调控NLRP3小体激活是碳黑致肺组织损伤的机制之一；（5）micRNA-126调控的PI3K/AKT/mTOR信号通路是碳黑致肺组织纤维化的机制之一。.该项目为寻找纳米级碳黑在致人群呼吸系统疾病和遗传损伤终点出现之前的早期健康效应指标，发现纳米级碳黑致肺组织损伤中的作用机制，为制定相应的职业或环境卫生标准提供科学依据，为预防纳米颗粒物引起的呼吸系统损伤寻找治疗靶点。